Overwintering Onions

Originally as a part of a project on Winter Harvest and Sales of Vegetables, we began to study the possibility of overwintering fall-planted onions in low tunnels for spring harvest. Our preliminary objectives were to find out whether it was possible, and to determine which factors influence success.Many partners were involved in this work, including Heather Bryant, UNH Extension Field Specialist in Grafton County, and collaborators at the University of Massachusetts, Seacoast Eat Local, and Communities Involved in Sustaining Agriculture.

In 2014, we expanded this work to include high tunnels, and focused our research objectives. Our main objectives now are to identify onion varieties (especially red ones) that work well in this production system, and to determine the effects of planting date on bulb development and bolting in the spring. Our most recent report is now available: Overwintering onions research report: plantain dates and varieties 2015